ABSTRACT
The transition element vanadium exists mostly in the 3, 4, and 5 oxidation states (Table 21.1), with the 4 and 5 states predominating under oxidizing conditions in the normal soil acidity of below pH 8 (1,2). Vanadium, with many other heavy metals, is released by anthropogenic activity, and its concentration has been steadily increasing in the environment. A study on peat dating back 12,370 years from a bog in Switzerland indicated a large increase in inputs of vanadium since the industrial revolution (3). Analysis of herbarium specimens of 24 species of vascular plants and 3 bryophytes collected over many years in Spain has shown a large increase in leaf vanadium concentrations, particularly since the 1960s (4).
